In 2014, Libya was gripped by a vicious civil war. Despite being monitored by British security officials, Abedi and his brother Hashem travelled to Libya. He was then one of 100 British citizens who needed to be evacuated from Tripoli due to the conflict.

"During the deteriorating security situation in Libya in 2014, Border Force officials were deployed to assist with the evacuation of British nationals and their dependents," a UK government spokesman told media.

According to reports, Abedi, then aged 19, was rescued from Libya by the HMS Enterprise before being taken to Malta where he caught a flight back to the UK.

"He was a British citizen so it was our job to safeguard him. Salman was one of many people in that mix and we absolutely had to evacuate him," a senior security source told the Daily Mail.

"He was not a threat at the time and it was in a very different context."

A family friend told the paper Abedi was in Libya for peaceful purposes, not to participate in the conflict.

"Salman and Hashem were not involved in fighting at all and they had spent a lot of time with their mother in Tunisia," they said.

However his actions against the country which helped save his life have angered and appalled Britain.

"For this man to have committed such an atrocity on UK soil after we rescued him from Libya was an act of utter betrayal," a Whitehall source told the Daily Mail.